Keep the stock switch in one head/ sender in the other head setup- with stock gauge? Aftermarket sender in one head with aftermarket gauge? Two senders - Two gauges? Can one gauge be used with two senders, and show the higher reading of the two? I'd really like to keep tabs on both heads- educate me! Thanks, Rich
While I have yet to get mine up and running, here's my thoughts. I plan to use a mechanical temp for each head. I think the original gauge reading was the "average" of the two head temps (correct me if I'm wrong). The advantage of two gauges is that you would know which side is hotter than the other...
On stockers from 1940-end, there are two senders hooked together; The one with a single terminal is a true sender that moves the gauge, the one with two terminals in the other side is a PANIC! button that just switches at a set temp and pegs the gauge--same idea as an idiot light. Stock setup is adequate on a de-bugged engine known to be running happily at its thermostat setting. You could add a second sender in place of the panic device and put in a selector switch, but if you need such constant monitoring you need some more work on the engine before hitting the road! Or mebbe sedatives... Before running stock or any electric gauge with a new engine, though, I'd do the shakedown with a known good (test it in boiling water on stove) mechanical gauge to get known readings AND to teach me what the cryptic marks on the stock gauge really mean. It would probably make sense to just keep the mechanical gauge in one head and the stock sender unit in the other--that's my system. If not running a heater that needs the other available opening(s) and if a bit of extra junk isn't a problem, I think idiot lights for oil and temp both are a good idea, though I've never run them. An idiot light is better than a gauge for a sudden failure! For general running on a healthy engine, single-side gauge is fine, as water mixes in the radiator and you'll know if you have a creeping problem. If there's a sudden, violent event, like a hose blowing off or a thermostat failing, double gauges might well pay for themselves--but problems like that are spectacular enough that there might only be a second or two between first flicker of the gauge and a geyser appearing in front of your windshield.
That's the first time someone has explained that system. Thanks Bruce. I put a 50 8ba in my 41 truck. I kept all the temperature senders, wiring, and gauges from the 41, which are the style Bruce mentions above. So I'm running all stock temp senders and gauges as they came from the factory I also bought new water pumps from Speedway that have the water outlet for the heater core. I bought two Moon temp gauges and put them in the water outlet holes. One on each water pump. The threads match so it was easy. I don't run a heater. Water Pumps Moon Gauges I can run the motor and get a temperature reading with the Moon gauges and I check it against the gauge in the dash to see how they all figure. This system does not give you a way to see the exact temp of each head in the cab, but its fine with me. Mike
Baron Von Mike, What's the reasoning behind a direct mount gauge? I understand that for fuel it's a good idea, but why water temp? How do you see it when you're driving?
I did it because the previous owner (a very good electrician) converted the 6v car to 12v. I wanted know what the stock temp gauge in the dash related to in actual farenheight. At the end of my post I state that I can't see the individual temps from inside the cab. I've learned that when stock gauge in the dash is a little over 1/2, I'm at 180. When it gets to about 3/4, I'm at 190. I'm lucky in that its never pegged. I've done all my testing in the driveway and a few times I've pulled off the freeway and immediately opened the hood and watched the Moon gauges. I've never gone over 190 with my motor. The stock gauge has worked in sync with the mechanical gauges to my satisfaction so I'm done. But there may be others of you that want more exact readings while in the driver's seat. I thought his question was more about fielding ideas. Maybe my solution is too brain dead? Mike
I don't think so Mike. Tinkering with the engine (carb, etc) would allow you to keep an eye on the temp with the Moon gauge(s) while sitting in the driveway.
I have schematics of the electrical system including the fauges for the 8BA's. I run the stock temperature gauge on my blown Merc. Bruce (as usual) is right in the fact that the left head sender is nothing more than a panic switch and the right head, single pole, sender positions the dash gauge pointer. Only clarification I can add is that the dash gauge goes to low temperature when the current through the system is the highest and when current goes low the gauge increases in temperature. This is easily proven because the gauge goes to the FULL HOT position when the ignition key is turned off. When the key is turned on the pointer goes to the correct temperature. With that said, if the left head sender (switch) opens because of a temperture exceeding around 210 degrees the dash gauge goes to the FULL HOT position as if the key were turned off. I calibrated my system to obtain mid pointer positon when the engine temperature is 160 degrees and verified with a laser infared gun on the right head.
I run the direct mount MOON gauges in the heads of mine. I can see the driver's side and check the pass side on hot days at lights or stop signs. Just gotta unbelt and stand up to see it. Works good. and it runs 160 all day long. On a recent 95 degree day, it got up bout 190 but ran fine.
I use one guage, two single pole senders and a toggle switch. It enables me to toggle to either head to see temp. Run the wires from the senders to the toggle switch, then a wire to the guage.
I use two mechanacal aftermarket gages[never can have too many gages] I like them as thay work with no electrical conection execpt lighting. Just dont short out the gas filled tubes aginst any electric device like volte meter or amp gage.Dont ask how i know.had to buy a new one.
Alternatively, you can do what I did yesterday - cover the gauge because you don't like what it's telling you & wait until the coolant sprays onto the windshield heavily enough that you need to turn on your wipers... ...then it's too hot!
I picked up 2 direct mount marine temp gauges (1 for each head-31 A coupe 8BA) and a sender for an idiot lite that is set to switch on at 220F. You can buy senders for lites set at different temps (NAPA). With antifreeze and a 8lb radiator cap my coolant boiling point should be over the 220F mark. I can stop and check the gauges periodically to see how it runs normally-if the light comes on-OH SHIT!!! overspray
I want to run two SW mechanical temp gauges, but for now I only have one in one head. The other head I have the single pole stock sender hooked to the stock gauge. I see when my stock gauge is straight up the temp is about 170 on the SW. The stock senders peg the stock gauge at 200. So far it's been working good, but I'm still looking for another SW.
[I have 2 stewart warner gauges, one in each head. The Drivers side seems to run 5 degrees cooler than the passenger side on mine, I switched the gauges to make sure it wasn't just one gauge reading different from the other. Roy
I can't see my senders in my '53 so I put oil press. and two temp gauges under the dash. Keeps my dash clean and lets me know whats going on. -slacker
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